the azure vault above and the yellow Styx below ❍ 上穷碧落下黄泉，两处茫茫皆不见。(白居易《长恨歌》) Above he searched the azure vault,|The yellow Styx below; |Both stretched in gloomy emptiness,|Nor traces of her show.
碧落黄泉bì luò huánɡ quán
碧落：天上；黄泉：指地下。天上和地下。指宇宙的每个角落。every corner of the world, every corner of the universe